We extend single-porosity flow diagnostics to dual-porosity systems using a novel retardation factor R to account for the effect of fracture-matrix transfer on breakthrough times and displacement efficiency during two-phase flow in fractured reservoirs. R is based on an analytical solution for capillary-driven fluid exchange between the fractures and rock matrix. By linearizing R the time-of-flight τ^⋆ is adjusted to include fracture-matrix transfer and derive new metrics, the dynamic Lorenz coefficient to quantify the dynamic heterogeneity, and the dual-porosity sweep efficiency Ev^⋆ to estimate how efficiently the injected fluid displaces the reservoir fluid over time. We have tested different formulations of R across three case studies with increasing complexity to analyze the applicability and limitations of dual-porosity flow diagnostics. This analysis reveals that as long as flow in the fractures is faster than fracture-matrix transfer, dual-porosity flow diagnostics provide useful approximations when assessing displacement efficiencies and identifying the wells that are at most and least likely to experience early breakthrough. We show that and Ev^⋆ can be combined with stochastic optimization algorithms to improve the displacement efficiency in a 3D reservoir case study. Since a single dual-porosity flow diagnostics calculation requires less than 1 min while a full-physics simulation takes 2 h, we can now quickly screen a large parameter space to identify scenarios that need to be studied in more detail using full-physics simulations. Hence, our new dual-porosity flow diagnostics complement and accelerate state-of-the-art uncertainty quantification and optimization workflows for fractured reservoirs.

中文翻译：

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天然裂缝性油藏自发渗入的双孔渗流诊断

我们将新颖的阻滞因子R扩展到双孔隙度系统的单孔隙度流体诊断，以解决裂缝性油藏在两相流过程中裂缝基质转移对突破时间和驱替效率的影响。R基于裂缝和岩石基质之间毛细管驱动流体交换的解析解决方案。通过线性化ř时间飞行的τ ^⋆被调整为包括骨折矩阵传递并导出新指标，动态洛伦茨系数量化动态的异构性以及双重孔隙波及效率EV ^⋆以估计注入的流体随时间推移驱替储层流体的效率。我们已经在三个案例研究中测试了R的不同配方，并且越来越复杂，以分析双孔隙流诊断的适用性和局限性。该分析表明，只要裂缝中的流动比裂缝-基质转移要快，在评估驱替效率和确定最多且最少可能经历早期突破的油井时，双孔渗流诊断就可以提供有用的近似值。我们发现，与EV ^⋆可以与随机优化算法结合使用，以提高3D油藏案例研究中的驱油效率。由于单个双孔隙流诊断计算所需的时间少于1分钟，而全物理模拟需要2小时，因此我们现在可以快速筛选大型参数空间，以识别需要使用全物理模拟进行更详细研究的方案。因此，我们的新型双孔隙流诊断技术可补充和加速裂缝性油藏的最新不确定性量化和优化工作流程。